1. Field of the Invention
The present invention relates to a paper supply module with which a copier, printer, facsimile machine, or other such image forming apparatus might be equipped, and to an image forming apparatus equipped with such a paper supply module; and also to a paper supply mechanism with which same might be equipped, and to an image forming apparatus equipped with such a paper supply mechanism. In particular, the present invention relates to improvements in paper supply modules and paper supply mechanisms constructed so as to permit reduction in the amount of space required for image forming apparatus installation and/or reduction in the frequency of occurrence of paper jams.
2. Description of the Related Art
Copiers, printers, facsimile machines, and other such image forming apparatuses—as well as hybrid devices equipped with a plurality of such functions in combination—have conventionally been equipped with automatic-feed cassettes and manual-feed trays serving as containers for (platforms for placement of) recording paper to be fed to image forming units (printing units) equipped with photosensitive drums and the like. When several hundred sheets of recording paper are, for example, loaded into an automatic-feed cassette and image formation is carried out on this recording paper, the recording paper might be sequentially taken up from the automatic-feed cassette and fed to an image forming unit. On the other hand, when a user places recording paper (e.g., postcard stock or the like) on a manual-feed tray and causes initiation of image forming operations, recording paper on this manual-feed tray might be fed to an image forming unit.
Image forming apparatuses equipped with such automatic-feed cassette(s) and manual-feed tray(s) are, for example, disclosed at Japanese Patent Application Publication Kokai No. 2001-138576 and Japanese Patent Application Publication Kokai No. 2001-333249. As disclosed in these references, the automatic-feed cassette has heretofore typically been provided at the lowermost part of the apparatus, with the paper supply path extending from the discharge side of this automatic-feed cassette to the image forming unit. Furthermore, the manual-feed tray, being attached to a side wall of the image forming apparatus, has communicated with an intermediate location along the foregoing paper supply path by way of a paper pickup mechanism for taking up recording paper from this manual-feed tray.
FIG. 14 shows in schematic fashion the internal constitution of a typical conventional copier. At this FIG. 14, a is an automatic-feed cassette; b is a manual-feed tray; c is an image forming unit equipped with a photosensitive drum and so forth; d is a paper supply path extending from automatic-feed cassette a; and e is a paper pickup mechanism for taking up recording paper from manual-feed tray b.
As can be seen in FIG. 14, in the case of a paper supply system having layout as mentioned above in which automatic-feed cassettes a are provided at the lowermost part of an image forming apparatus and manual-feed tray b is provided at a side wall of the image forming apparatus, paper pickup mechanism e for manual-feed tray b is arranged to one side of paper supply path d (i.e., at the side thereof nearer to the apparatus side wall), and paper supply path d extends from automatic-feed cassette a so as to be directed toward image forming unit c; meaning that manual-feed tray b will, moreover, be arranged to one side of paper pickup mechanism e. In other words, the aforementioned paper pickup mechanism e and manual-feed tray b are arranged, in that order as one goes toward the exterior horizontally, to one side of paper supply path d; the presence of these meaning that there has been a limit to the degree to which it has been possible to reduce the amount of space required for installation of the image forming apparatus. In the case of this image forming apparatus shown in FIG. 14, were it not for manual-feed tray b and paper pickup mechanism e the amount of space required for installation of the apparatus would only be dimension I shown in the drawing, but due to the fact that manual-feed tray b and paper pickup mechanism e are actually present the amount of space required for installation of the apparatus is dimension II.
At the same time, developments have in recent years been underway in efforts to achieve reduction in the amount of space required for installation of the apparatus by arranging the automatic-feed cassette at the lower portion of the apparatus and arranging the original capturing unit (scanning unit) at the upper portion of the apparatus, and by disposing the image forming unit and discharge unit (discharge tray) between this automatic-feed cassette and this original capturing unit so as to avoid situations in which the discharge tray protrudes from the side of the apparatus.
FIG. 15 shows in schematic fashion an image forming apparatus having such a layout. At this FIG. 15 as well, a is an automatic-feed cassette; b is a manual-feed tray; c is an image forming unit; d is a paper supply path; and e is a paper pickup mechanism. In the case of an image forming apparatus having such a layout, because the aforementioned paper pickup mechanism e and manual-feed tray b are arranged, in that order as one goes toward the exterior horizontally, at the peripheral region near the side wall of the apparatus, as was the case in the above situation there has here as well been a limit to the degree to which it has been possible to reduce the amount of space required for installation.
In particular, given such a layout, it will be necessary to arrange flipping transport path (switchback transport path) f, for flipping of recording media when carrying out double-sided printing, to one side of paper supply path d. And in the case of a layout in which the aforementioned paper pickup mechanism e and manual-feed tray b are arranged even further to the side than this flipping transport path f, because the space required for installation of the apparatus will increase by an amount corresponding thereto, it has not been possible to take full advantage of the reduction in installation space that would otherwise be afforded by the aforementioned layout (i.e., layouts having the intention of avoiding situations in which the discharge tray protrudes from the side of the apparatus). At this FIG. 15 as well, the amount of space that would be required for installation were it not for manual-feed tray b and paper pickup mechanism e is indicated by I, and the amount of space required for installation of the apparatus due to the fact that manual-feed tray b and paper pickup mechanism e are present is indicated by II.
Furthermore, the paper supply path in heretofore-developed image forming apparatuses has been such that the transport path for recording paper supplied from the automatic-feed cassette and the transport path for recording paper supplied from the manual-feed tray have intersected at a location immediately upstream from the image forming unit, and the overall paper supply path of the image forming apparatus has been quite long, increasing by a corresponding amount the complexity of the internal constitution within the apparatus main body as well as the number of locations at which paper jams can occur, and making reduction in the frequency of occurrence of paper jams difficult.
The present invention was conceived in light of such issues, it being an object thereof to provide a hybrid paper supply module permitting reduction in the amount of space required for image forming apparatus installation as well as reduction in the frequency of occurrence of paper jams, and an image forming apparatus equipped with such hybrid paper supply module(s).